The get_buffers() macro may provide one or two buffers to the caller.
Those buffers are pre-allocated on init for each CPU. By default it
allocates
2* 2 * MAX_PATH * POSSIBLE_CPU
which equals 64KiB on a system with 4 CPUs or 1MiB with 64 CPUs and so
on.
Replace the per-CPU buffers with a common memory pool which is shared
across all CPUs. The pool grows on demand and never shrinks. The pool
starts with two (UP) or four (SMP) elements. By using this pool it is
possible to request a buffer and keeping preemption enabled which avoids
the hack in profile_transition().
It has been pointed out by Tetsuo Handa that GFP_KERNEL allocations for
small amount of memory do not fail. In order not to have an endless
retry, __GFP_RETRY_MAYFAIL is passed (so the memory allocation is not
repeated until success) and retried once hoping that in the meantime a
buffer has been returned to the pool. Since now NULL is possible all
allocation paths check the buffer pointer and return -ENOMEM on failure.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Refactor get_buffers so the cpu_ptr can be obtained in the outer
layer, instead of inside the macro.
This also enables us to cleanup the code and use get_cpu_ptr,
to handle the preempt_disable()
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
move COUNT_ARGS() macro from apparmor to generic header and extend it
to count till twelve.
COUNT() was an alternative name for this logic, but it's used for
different purpose in many other places.
Similarly for CONCATENATE() macro.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Dynamically allocating buffers is problematic and is an extra layer
that is a potntial point of failure and can slow down mediation.
Change path lookup to use the preallocated per cpu buffers.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Move the path name lookup failure messages into the main path name lookup
routine, as the information is useful in more than just aa_path_perm.
Also rename aa_get_name to aa_path_name as it is not getting a reference
counted object with a corresponding put fn.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Miscellaneous functions and defines needed by AppArmor, including
the base path resolution routines.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
